Tag Archives: polyacrylamide gel

Analysis of chitosan molecular weight profile by electrophoresis in a porosity step gradient polyacrylamide gel

M. D. Lootsik1*, N. O. Manko1, R. O. Bilyy2,
M. M. Lutsyk (Jr.)2, R. S. Stoika1

1Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv;
2Danylo Halytsky National Medical University, Lviv, Ukraine;
*e-mail: lootsikmaxim@gmail.com

Received: 12 April 2022; Accepted: 01 July 2022

Chitosan is biocompatible and biodegradable natural biopolymer widely applied in various fields of biology, medicine, and pharmacy, however, its effects significantly depend on the degree of polymerization (DP) and the degree of deacetylation (DDA) of polymer chains. Evaluation of the chitosan chain diversity by DP requires the use of a highly expensive method of high-performance size exclusion chromatography. The aim of our study was to determine the molecular weight profile of chitosan specimens by the use of electrophoresis in a porosity step gradient polyacrylamide gel and to evaluate the efficacy of this method in monitoring the purification of chitosan fragments and its derivatives. Two types of step gradient porosity gels were used: 1) gels of layers with acrylamide concentration 2.5, 3.5, 5.0, 10.0, 15.0, 20.0 % w/v for native chitosan or its high molecular fragments; 2) gels of layers with acrylamide concentration 2.5, 5.0, 10.0, 15.0, 20.0, 25.0 % w/v for low molecular chitosan fragments. The main amount of molecules from the chitosan pool was localized in the type 1 gel in the region of 550-40 kDa and distributed among three bands, which in different samples differed significantly in percentage. Electrophoresis of chitosan fragments fractionated by gel permeation chromatography provided a clear separation of medium molecular weight fragments (50–400 kDa) in type 1 gel and of low molecular weight fragments (3–40 kDa) in type 2 gel. Thus the method of chitosan electrophoresis in a step-gradient porosity of polyacrylamide gel was developed which permits to characterize the molecular weight profile of chitosan specimens polymer chains and is effective in monitoring the isolation of chitosan fragments by gel penetration chromatography of molecular weights from 3 to 400 kDa.

Purification procedure and assay for the activity of lysyl oxidase

O. O. Gudkova, N. V. Latyshko, O. V. Zaitseva, S. G. Shandrenko

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: gudkovahelga@gmail.com

The goal of the present study was to extract and purify lysyl oxidase from rodent’s tissues by a fast, simple, effective and inexpensive method and to develop a sensitive, time-saving lysyl oxidase specific activity assay for routine in vitro experiments. Lysyl oxidase was purified by elaborated purification procedure which relies on negative adsorption principle, that is, an effective decrease in the concentration of ballast components by the polar hydrophilic adsorbent and increasing the concentration of the protein of interest. Peroxide-coupled lysyl oxidase activity quantification methods based on luminol chemiluminescence in the presence of horseradish peroxidase as a catalyst and fluorescent detection using folic acid and Cu(II)  with 1,5-diaminopentane as the substrate, were designed. Lysyl oxidase was partially purified from urea extracts of rodent’s tissues. Used purification procedure ensures the fast release of 93% of ballast proteins as shown by polyacrylamide gel electrophoresis. Lysyl oxidase specific activity after purification was 10-22-fold higher than that of the original extract. The molecular mass of murine lysyl oxidase from lung and heart was estimated to be ~32 kDa. We elaborated two sensitive methods for lysyl oxidase activity quantification and fast inexpensive procedure for partial enzyme purification useful in bulky in vitro experiments.